Effects of agricultural activities on soil inorganic nitrogen along an altitudinal gradient in the Medog subtropical forest,Southeastern Tibetan Plateau

doi:10.7523/j.ucas.2023.043

Abstract

Abstract: Soil inorganic nitrogen (SIN, NH₄⁺-N and NO₃^--N) is a vital indicator of soil N supply. Studying the current status of farmlands’ SIN on the Tibetan Plateau is important to achieve the sustainability of plateau agriculture development. 10 pairs of farmland and forest soils were collected along the sampling gradient from 800 to 2 000 m (a.s.l.) in Medog of southeastern Tibet, to investigate the effects of agricultural activities on SIN and clarify the environmental drivers of SIN. The results have shown that human activities significantly changed the concentration and spatial distribution pattern of SIN in farmlands. The topsoil (0 ~ 10 cm) was vulnerable to human activities. NH₄⁺-N concentration of topsoil decreased significantly and NO₃^--N concentration increased significantly after reclamation. The SIN of the forests did not differ significantly among layers, but large differences were seen in the farmlands’ SIN among layers. SIN in forest ecosystems was influenced by altitude, soil temperature, soil moisture, and pH, while agricultural ecosystems were not sensitive to environmental factors. The change amount of SIN after reclamation was mainly determined by soil temperature and soil pH. In conclusion, reasonable agricultural management is necessary to achieve sustainable development of regional agriculture.

Key words: Southeastern Tibet, transect sampling, farmlands, soil inorganic nitrogen

CLC Number:

S154.1

LEI Haojing, Xu-Ri, QU Songbo, Shamaribu, LI Fengzi, ZHANG Lin, LIANG Eryuan. Effects of agricultural activities on soil inorganic nitrogen along an altitudinal gradient in the Medog subtropical forest,Southeastern Tibetan Plateau[J]. Journal of University of Chinese Academy of Sciences, DOI: 10.7523/j.ucas.2023.043.

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